Radical copolymerization of N-vinylcarbazole and p-bromostyrene: determination of monomer reactivity ratios by SEC-multidetection

N-Vinylcarbazole (A)/p-bromostyrene (B) copolymers were prepared by radical copolymerization. Size exclusion chromatography (SEC) equipped with a refractometer and UV-vis spectrophotometer was found to be a very convenient technique to follow copolymerizations and to determine monomer conversions, copolymer composition, average molecular weights, polydispersity indexes versus time. The monomer reactivity ratios r_A (N-vinylcarbazole) and r_B (p-bromostyrene) were determined by using the Finemann-Ross (FR), the inverted Finemann-Ross (IFR), the Kelen-Tüdos (KT), and the fitting curve graphical methods. The four methods were in good agreement and led to very different values for r_A (0.55) and r_B (12.3) which induces a preference for the incorporation of B in the copolymer structure. Eventually, with these results the influence of initial feed on the microstructure of the copolymer has been predicted.     

Dilatometric investigations of fats. VI. Melting dilation as a function of chain length in fatty acids and their glyceryl esters

Melting dilations have been determined for the even-numbered, saturatedn-fatty acids in the series lauric through stearic, and some of their glyceryl esters. These data have been correlated with data obtained previously to determine the relationship between melting dilation and the effective chain length of these compounds. The melting dilations of the mono-, di-, and triglyceryl esters of a fatty acid were found to be proportional to the acid residue content of each compound. The melting dilation of a monoglyceride was one-half that of the diglyceride and one-third that of the triglyceride of the same fatty acid. The increment of melting dilation of the fatty acids and glyceryl esters increased regularly with each addition of two methylene groups, with the end group components exerting a contant effect on the volume change. Equations were developed for calculating the melting dilation of then-fatty acids and their glycerides as a function of chain length of the fatty acid radical. The melting dilations of those compounds which are unsaturated, or have less than 10 carbon atoms, cannot be calculated by these equations.     

Dynamic Real-time Scheduling of Firm Periodic Tasks with Hard and Soft Aperiodic Tasks

In this paper, we address the problem of the dynamic scheduling of skippable periodic task sets (i.e., period tasks allowing occasional skips of instances), together with aperiodic tasks. Scheduling of tasks is handled thanks to the merging of two existing approaches: the Skip-Over task model and the EDL (Earliest Deadline as Late as possible) aperiodic task server. The objective is to provide two on-line scheduling algorithms, namely EDL-RTO and EDL-BWP, in order to minimize the average response time of soft aperiodic requests, while ensuring that the QoS (Quality of Service) of periodic tasks will never be less than a specified bound. We also extend our results to the acceptance of sporadic tasks (i.e., aperiodic tasks with deadlines). We show that these novel scheduling algorithms have better performance compared to related algorithms regarding aperiodic response time and acceptance ratio. Audrey Marchand guaduated in Computer Engineering at the Ecole polytechnique of the University of Nantes (France), in 2002. She is currently a PhD student at the University of Nantes. Her research interests include real-time scheduling theory, aperiodic service mechanisms, quality of service guarantees in soft real-time systems, and Linux-based real-time operating systems and applications. Maryline Chetto received the degree of Docteur de 3ème cycle in control engineering and the degree of Habilitée à Diriger des Recherches in Computer Science from the University of Nantes, France, in 1984 and 1993, respectively. From 1984 to 1985, she held the position of Assistant professor of Computer Science at the University of Rennes, while her research was with the Institut de Recherche en Informatique et Systèmes Aléatoires, Rennes. In 1986, she returned to Nantes and is currently a professor with the Institute of Technology of the University of Nantes. She is conducting her research at IRCCyN. Her main research interests include scheduling and fault-tolerance technologies for real-time applications. She has published more than 60 journal articles and conference papers in the area of real-time operating systems. She is the leader of a French national R&D project, namely Cleopatre, supported by the French government, which aims to provide free open source real-time solutions.     

Autonomous, broad-spectrum detection of hazardous aerosols in seconds

Actual or surrogate chemical, biological, radiological, nuclear, and explosive materials and illicit drug precursors can be rapidly detected and identified when in aerosol form by a Single-Particle Aerosol Mass Spectrometry (SPAMS) system. This entails not only the sampling of such particles but also the physical analysis and subsequent data analysis leading to a highly reliable alarm state. SPAMS hardware is briefly reviewed. SPAMS software algorithms are discussed in greater detail. A laboratory experiment involving actual threat and surrogate releases mixed with ambient background aerosols demonstrates broad-spectrum detection within seconds. Data from a field test at the San Francisco International Airport demonstrate extended field operation with an ultralow false alarm rate. Together these data sets demonstrate a significant and important advance in rapid aerosol threat detection.     

Incineration of municipal and assimilated wastes in France: assessment of latest energy and material recovery performances

Incineration has an important place in waste management in France. In 2003, around 130 incineration plants have treated 12.6 Mt of non-dangerous waste, mainly composed of household waste (10.8 Mt), non-dangerous waste from industry, business, services (1.0 Mt), sewage sludge (0.2 Mt) or clinical waste (0.1 Mt). The incineration of these wastes generated 3.0 Mt of bottom ash of which 2.3 Mt were used for roads construction and 0.2 Mt of ferrous and non-ferrous metal were recycled. It also produced 2,900,000 MWh of electricity, of which 2,200,000 MWh were sold to Electricité de France (EDF) and 9,100,000 MWh of heat, of which 7,200,000 MWh were sold to private or public users. These French incinerators of non-hazardous waste are currently being thoroughly modernized, thus making possible the consolidation and the enhancement of their environmental and energy performance. This process is related to the implementation of the European Directive 2000/76/CE whose expiration date is 28 December 2005. Upon request of ADEME, the engineering company GIRUS has realised the first technical and economical evaluation of works necessary to bring incinerators into compliance. The financial estimations, carried out in 30 June 2003, show that the investments to be devoted could reach 750 million euros. This assessment shed new light on the situation of non-hazardous waste incinerators, including an identification and a rank ordering for each incinerator of the most frequent and the most complex non-conformities to be solved in term of cost and delay. At last, this assessment gives the solutions for each non-compliance.     

Influence of the Martensitic Transformation on the Microscale Plastic Strain Heterogeneities in a Duplex Stainless Steel

The influence of the martensitic transformation on microscale plastic strain heterogeneity of a duplex stainless steel has been investigated. Microscale strain heterogeneities were measured by digital image correlation during an in situ tensile test within the SEM. The martensitic transformation was monitored in situ during tensile testing by high-energy synchrotron X-ray diffraction. A clear correlation is shown between the plasticity-induced transformation of austenite to martensite and the development of plastic strain heterogeneities at the phase level.     

Study of fuel efficiency in a direct borohydride fuel cell

In this study, direct borohydride fuel cells (DBFCs) potentialities are evaluated. These emerging systems make it possible to reach maximum powers of about 200 mW cm⁻² at room temperature and ambient air (natural convection) with high concentrated borohydride solutions. On the other hand, a part of borohydride hydrolyses during cell operating which leads to hydrogen formation and fuel loss: the practical capacity represents about only 18% of the theoretical one. In order to improve fuel efficiency, thiourea is tested as an inhibitor of the catalytic hydrolysis associated with BH₄⁻ electro-oxidation on Pt. The practical capacity is drastically improved: it represents about 64% of the theoretical one. Against, electrochemical performances (I–E curves) are affected by the presence of thiourea.